utils.c

   1 /*
   2  * firewall3 - 3rd OpenWrt UCI firewall implementation
   3  *
   4  *   Copyright (C) 2013 Jo-Philipp Wich <jow@openwrt.org>
   5  *
   6  * Permission to use, copy, modify, and/or distribute this software for any
   7  * purpose with or without fee is hereby granted, provided that the above
   8  * copyright notice and this permission notice appear in all copies.
   9  *
  10  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  */
  18
  19 #include "utils.h"
  20 #include "options.h"
  21
  22 #include "zones.h"
  23 #include "ipsets.h"
  24
  25
  26 static int lock_fd = -1;
  27 static pid_t pipe_pid = -1;
  28 static FILE *pipe_fd = NULL;
  29
  30 bool fw3_pr_debug = false;
  31
  32
  33 static void
  34 warn_elem_section_name(struct uci_section *s, bool find_name)
  35 {
  36         int i = 0;
  37         struct uci_option *o;
  38         struct uci_element *tmp;
  39
  40         if (s->anonymous)
  41         {
  42                 uci_foreach_element(&s->package->sections, tmp)
  43                 {
  44                         if (strcmp(uci_to_section(tmp)->type, s->type))
  45                                 continue;
  46
  47                         if (&s->e == tmp)
  48                                 break;
  49
  50                         i++;
  51                 }
  52
  53                 fprintf(stderr, "@%s[%d]", s->type, i);
  54
  55                 if (find_name)
  56                 {
  57                         uci_foreach_element(&s->options, tmp)
  58                         {
  59                                 o = uci_to_option(tmp);
  60
  61                                 if (!strcmp(tmp->name, "name") && (o->type == UCI_TYPE_STRING))
  62                                 {
  63                                         fprintf(stderr, " (%s)", o->v.string);
  64                                         break;
  65                                 }
  66                         }
  67                 }
  68         }
  69         else
  70         {
  71                 fprintf(stderr, "'%s'", s->e.name);
  72         }
  73
  74         if (find_name)
  75                 fprintf(stderr, " ");
  76 }
  77
  78 void
  79 warn_elem(struct uci_element *e, const char *format, ...)
  80 {
  81         if (e->type == UCI_TYPE_SECTION)
  82         {
  83                 fprintf(stderr, "Warning: Section ");
  84                 warn_elem_section_name(uci_to_section(e), true);
  85         }
  86         else if (e->type == UCI_TYPE_OPTION)
  87         {
  88                 fprintf(stderr, "Warning: Option ");
  89                 warn_elem_section_name(uci_to_option(e)->section, false);
  90                 fprintf(stderr, ".%s ", e->name);
  91         }
  92
  93     va_list argptr;
  94     va_start(argptr, format);
  95     vfprintf(stderr, format, argptr);
  96     va_end(argptr);
  97
  98         fprintf(stderr, "\n");
  99 }
 100
 101 void
 102 warn(const char* format, ...)
 103 {
 104         fprintf(stderr, "Warning: ");
 105     va_list argptr;
 106     va_start(argptr, format);
 107     vfprintf(stderr, format, argptr);
 108     va_end(argptr);
 109         fprintf(stderr, "\n");
 110 }
 111
 112 void
 113 error(const char* format, ...)
 114 {
 115         fprintf(stderr, "Error: ");
 116     va_list argptr;
 117     va_start(argptr, format);
 118     vfprintf(stderr, format, argptr);
 119     va_end(argptr);
 120         fprintf(stderr, "\n");
 121
 122         exit(1);
 123 }
 124
 125 void
 126 info(const char* format, ...)
 127 {
 128         va_list argptr;
 129     va_start(argptr, format);
 130     vfprintf(stderr, format, argptr);
 131     va_end(argptr);
 132         fprintf(stderr, "\n");
 133 }
 134
 135 const char *
 136 fw3_find_command(const char *cmd)
 137 {
 138         struct stat s;
 139         int plen = 0, clen = strlen(cmd) + 1;
 140         char *search, *p;
 141         static char path[PATH_MAX];
 142
 143         if (!stat(cmd, &s) && S_ISREG(s.st_mode))
 144                 return cmd;
 145
 146         search = getenv("PATH");
 147
 148         if (!search)
 149                 search = "/bin:/usr/bin:/sbin:/usr/sbin";
 150
 151         p = search;
 152
 153         do
 154         {
 155                 if (*p != ':' && *p != '\0')
 156                         continue;
 157
 158                 plen = p - search;
 159
 160                 if ((plen + clen) >= sizeof(path))
 161                         continue;
 162
 163                 strncpy(path, search, plen);
 164                 sprintf(path + plen, "/%s", cmd);
 165
 166                 if (!stat(path, &s) && S_ISREG(s.st_mode))
 167                         return path;
 168
 169                 search = p + 1;
 170         }
 171         while (*p++);
 172
 173         return NULL;
 174 }
 175
 176 bool
 177 fw3_stdout_pipe(void)
 178 {
 179         pipe_fd = stdout;
 180         return true;
 181 }
 182
 183 bool
 184 __fw3_command_pipe(bool silent, const char *command, ...)
 185 {
 186         pid_t pid;
 187         va_list argp;
 188         int pfds[2];
 189         int argn;
 190         char *arg, **args, **tmp;
 191
 192         command = fw3_find_command(command);
 193
 194         if (!command)
 195                 return false;
 196
 197         if (pipe(pfds))
 198                 return false;
 199
 200         argn = 2;
 201         args = malloc(argn * sizeof(arg));
 202
 203         if (!args)
 204                 return false;
 205
 206         args[0] = (char *)command;
 207         args[1] = NULL;
 208
 209         va_start(argp, command);
 210
 211         while ((arg = va_arg(argp, char *)) != NULL)
 212         {
 213                 tmp = realloc(args, ++argn * sizeof(arg));
 214
 215                 if (!tmp)
 216                         break;
 217
 218                 args = tmp;
 219                 args[argn-2] = arg;
 220                 args[argn-1] = NULL;
 221         }
 222
 223         va_end(argp);
 224
 225         switch ((pid = fork()))
 226         {
 227         case -1:
 228                 return false;
 229
 230         case 0:
 231                 dup2(pfds[0], 0);
 232
 233                 close(pfds[0]);
 234                 close(pfds[1]);
 235
 236                 close(1);
 237
 238                 if (silent)
 239                         close(2);
 240
 241                 execv(command, args);
 242
 243         default:
 244                 signal(SIGPIPE, SIG_IGN);
 245                 pipe_pid = pid;
 246                 close(pfds[0]);
 247                 fcntl(pfds[1], F_SETFD, fcntl(pfds[1], F_GETFD) | FD_CLOEXEC);
 248         }
 249
 250         pipe_fd = fdopen(pfds[1], "w");
 251         return true;
 252 }
 253
 254 void
 255 fw3_pr(const char *fmt, ...)
 256 {
 257         va_list args;
 258
 259         if (fw3_pr_debug && pipe_fd != stdout)
 260         {
 261                 va_start(args, fmt);
 262                 vfprintf(stderr, fmt, args);
 263                 va_end(args);
 264         }
 265
 266         va_start(args, fmt);
 267         vfprintf(pipe_fd, fmt, args);
 268         va_end(args);
 269 }
 270
 271 void
 272 fw3_command_close(void)
 273 {
 274         if (pipe_fd && pipe_fd != stdout)
 275                 fclose(pipe_fd);
 276
 277         if (pipe_pid > -1)
 278                 waitpid(pipe_pid, NULL, 0);
 279
 280         signal(SIGPIPE, SIG_DFL);
 281
 282         pipe_fd = NULL;
 283         pipe_pid = -1;
 284 }
 285
 286 bool
 287 fw3_has_table(bool ipv6, const char *table)
 288 {
 289         FILE *f;
 290
 291         char line[12];
 292         bool seen = false;
 293
 294         const char *path = ipv6
 295                 ? "/proc/net/ip6_tables_names" : "/proc/net/ip_tables_names";
 296
 297         if (!(f = fopen(path, "r")))
 298                 return false;
 299
 300         while (fgets(line, sizeof(line), f))
 301         {
 302                 if (!strncmp(line, table, strlen(table)))
 303                 {
 304                         seen = true;
 305                         break;
 306                 }
 307         }
 308
 309         fclose(f);
 310
 311         return seen;
 312 }
 313
 314
 315 bool
 316 fw3_lock(void)
 317 {
 318         lock_fd = open(FW3_LOCKFILE, O_CREAT|O_WRONLY, S_IRUSR|S_IWUSR);
 319
 320         if (lock_fd < 0)
 321         {
 322                 warn("Cannot create lock file %s: %s", FW3_LOCKFILE, strerror(errno));
 323                 return false;
 324         }
 325
 326         if (flock(lock_fd, LOCK_EX))
 327         {
 328                 warn("Cannot acquire exclusive lock: %s", strerror(errno));
 329                 return false;
 330         }
 331
 332         return true;
 333 }
 334
 335 void
 336 fw3_unlock(void)
 337 {
 338         if (lock_fd < 0)
 339                 return;
 340
 341         if (flock(lock_fd, LOCK_UN))
 342                 warn("Cannot release exclusive lock: %s", strerror(errno));
 343
 344         close(lock_fd);
 345         unlink(FW3_LOCKFILE);
 346
 347         lock_fd = -1;
 348 }
 349
 350
 351 static void
 352 write_defaults_uci(struct uci_context *ctx, struct fw3_defaults *d,
 353                    struct uci_package *dest)
 354 {
 355         char buf[sizeof("0xffffffff\0")];
 356         struct uci_ptr ptr = { .p = dest };
 357
 358         uci_add_section(ctx, dest, "defaults", &ptr.s);
 359
 360         sprintf(buf, "0x%x", d->flags[0]);
 361         ptr.o      = NULL;
 362         ptr.option = "__flags_v4";
 363         ptr.value  = buf;
 364         uci_set(ctx, &ptr);
 365
 366         sprintf(buf, "0x%x", d->flags[1]);
 367         ptr.o      = NULL;
 368         ptr.option = "__flags_v6";
 369         ptr.value  = buf;
 370         uci_set(ctx, &ptr);
 371 }
 372
 373 static void
 374 write_zone_uci(struct uci_context *ctx, struct fw3_zone *z,
 375                struct uci_package *dest)
 376 {
 377         struct fw3_device *dev;
 378         struct fw3_address *sub;
 379         enum fw3_family fam = FW3_FAMILY_ANY;
 380
 381         char *p, buf[34];
 382
 383         struct uci_ptr ptr = { .p = dest };
 384
 385         if (!z->enabled)
 386                 return;
 387
 388         if (fw3_no_table(z->flags[0]) && !fw3_no_table(z->flags[1]))
 389                 fam = FW3_FAMILY_V6;
 390         else if (!fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 391                 fam = FW3_FAMILY_V4;
 392         else if (fw3_no_table(z->flags[0]) && fw3_no_table(z->flags[1]))
 393                 return;
 394
 395         uci_add_section(ctx, dest, "zone", &ptr.s);
 396
 397         ptr.o      = NULL;
 398         ptr.option = "name";
 399         ptr.value  = z->name;
 400         uci_set(ctx, &ptr);
 401
 402         ptr.o      = NULL;
 403         ptr.option = "input";
 404         ptr.value  = fw3_flag_names[z->policy_input];
 405         uci_set(ctx, &ptr);
 406
 407         ptr.o      = NULL;
 408         ptr.option = "output";
 409         ptr.value  = fw3_flag_names[z->policy_output];
 410         uci_set(ctx, &ptr);
 411
 412         ptr.o      = NULL;
 413         ptr.option = "forward";
 414         ptr.value  = fw3_flag_names[z->policy_forward];
 415         uci_set(ctx, &ptr);
 416
 417         ptr.o      = NULL;
 418         ptr.option = "masq";
 419         ptr.value  = z->masq ? "1" : "0";
 420         uci_set(ctx, &ptr);
 421
 422         ptr.o      = NULL;
 423         ptr.option = "conntrack";
 424         ptr.value  = z->conntrack ? "1" : "0";
 425         uci_set(ctx, &ptr);
 426
 427         ptr.o      = NULL;
 428         ptr.option = "mtu_fix";
 429         ptr.value  = z->mtu_fix ? "1" : "0";
 430         uci_set(ctx, &ptr);
 431
 432         ptr.o      = NULL;
 433         ptr.option = "custom_chains";
 434         ptr.value  = z->custom_chains ? "1" : "0";
 435         uci_set(ctx, &ptr);
 436
 437         if (fam != FW3_FAMILY_ANY)
 438         {
 439                 ptr.o      = NULL;
 440                 ptr.option = "family";
 441                 ptr.value  = fw3_flag_names[fam];
 442                 uci_set(ctx, &ptr);
 443         }
 444
 445         ptr.o      = NULL;
 446         ptr.option = "device";
 447
 448         fw3_foreach(dev, &z->devices)
 449         {
 450                 if (!dev)
 451                         continue;
 452
 453                 p = buf;
 454
 455                 if (dev->invert)
 456                         p += sprintf(p, "!");
 457
 458                 p += sprintf(p, "%s", dev->name);
 459
 460                 ptr.value = buf;
 461                 uci_add_list(ctx, &ptr);
 462         }
 463
 464         ptr.o      = NULL;
 465         ptr.option = "subnet";
 466
 467         fw3_foreach(sub, &z->subnets)
 468         {
 469                 if (!sub)
 470                         continue;
 471
 472                 ptr.value = fw3_address_to_string(sub, true);
 473                 uci_add_list(ctx, &ptr);
 474         }
 475
 476         sprintf(buf, "0x%x", z->flags[0]);
 477         ptr.o      = NULL;
 478         ptr.option = "__flags_v4";
 479         ptr.value  = buf;
 480         uci_set(ctx, &ptr);
 481
 482         sprintf(buf, "0x%x", z->flags[1]);
 483         ptr.o      = NULL;
 484         ptr.option = "__flags_v6";
 485         ptr.value  = buf;
 486         uci_set(ctx, &ptr);
 487 }
 488
 489 static void
 490 write_ipset_uci(struct uci_context *ctx, struct fw3_ipset *s,
 491                 struct uci_package *dest)
 492 {
 493         char buf[sizeof("0xffffffff\0")];
 494
 495         struct uci_ptr ptr = { .p = dest };
 496
 497         if (!s->enabled || (s->external && *s->external))
 498                 return;
 499
 500         uci_add_section(ctx, dest, "ipset", &ptr.s);
 501
 502         ptr.o      = NULL;
 503         ptr.option = "name";
 504         ptr.value  = s->name;
 505         uci_set(ctx, &ptr);
 506
 507         sprintf(buf, "0x%x", s->flags[0]);
 508         ptr.o      = NULL;
 509         ptr.option = "__flags_v4";
 510         ptr.value  = buf;
 511         uci_set(ctx, &ptr);
 512
 513         sprintf(buf, "0x%x", s->flags[1]);
 514         ptr.o      = NULL;
 515         ptr.option = "__flags_v6";
 516         ptr.value  = buf;
 517         uci_set(ctx, &ptr);
 518 }
 519
 520 void
 521 fw3_write_statefile(void *state)
 522 {
 523         FILE *sf;
 524         struct fw3_state *s = state;
 525         struct fw3_zone *z;
 526         struct fw3_ipset *i;
 527
 528         struct uci_package *p;
 529
 530         if (fw3_no_family(s->defaults.flags[0]) &&
 531             fw3_no_family(s->defaults.flags[1]))
 532         {
 533                 unlink(FW3_STATEFILE);
 534         }
 535         else
 536         {
 537                 sf = fopen(FW3_STATEFILE, "w+");
 538
 539                 if (!sf)
 540                 {
 541                         warn("Cannot create state %s: %s", FW3_STATEFILE, strerror(errno));
 542                         return;
 543                 }
 544
 545                 if ((p = uci_lookup_package(s->uci, "fw3_state")) != NULL)
 546                         uci_unload(s->uci, p);
 547
 548                 uci_import(s->uci, sf, "fw3_state", NULL, true);
 549
 550                 if ((p = uci_lookup_package(s->uci, "fw3_state")) != NULL)
 551                 {
 552                         write_defaults_uci(s->uci, &s->defaults, p);
 553
 554                         list_for_each_entry(z, &s->zones, list)
 555                                 write_zone_uci(s->uci, z, p);
 556
 557                         list_for_each_entry(i, &s->ipsets, list)
 558                                 write_ipset_uci(s->uci, i, p);
 559
 560                         uci_export(s->uci, sf, p, true);
 561                         uci_unload(s->uci, p);
 562                 }
 563
 564                 fclose(sf);
 565         }
 566 }
 567
 568
 569 void
 570 fw3_free_object(void *obj, const void *opts)
 571 {
 572         const struct fw3_option *ol;
 573         struct list_head *list, *cur, *tmp;
 574
 575         for (ol = opts; ol->name; ol++)
 576         {
 577                 if (!ol->elem_size)
 578                         continue;
 579
 580                 list = (struct list_head *)((char *)obj + ol->offset);
 581                 list_for_each_safe(cur, tmp, list)
 582                 {
 583                         list_del(cur);
 584                         free(cur);
 585                 }
 586         }
 587
 588         free(obj);
 589 }
 590
 591
 592 bool
 593 fw3_pr_rulespec(int table, int family, uint32_t *flags, uint32_t mask,
 594                 const struct fw3_rule_spec *r, const char *fmt, ...)
 595 {
 596         char buf[256];
 597         bool rv = false;
 598
 599         va_list ap;
 600         uint32_t f = flags ? flags[family == FW3_FAMILY_V6] : 0;
 601
 602         if (mask)
 603                 f &= mask;
 604
 605         for (; r->format; r++)
 606         {
 607                 if (!fw3_is_family(r, family))
 608                         continue;
 609
 610                 if (r->table != table)
 611                         continue;
 612
 613                 if ((r->flag != 0) && !hasbit(f, r->flag))
 614                         continue;
 615
 616                 va_start(ap, fmt);
 617                 vsnprintf(buf, sizeof(buf), r->format, ap);
 618                 va_end(ap);
 619
 620                 fw3_pr(fmt, buf);
 621
 622                 rv = true;
 623         }
 624
 625         return rv;
 626 }
 627
 628
 629 bool
 630 fw3_hotplug(bool add, void *zone, void *device)
 631 {
 632         struct fw3_zone *z = zone;
 633         struct fw3_device *d = device;
 634
 635         if (!d->network)
 636                 return false;
 637
 638         switch (fork())
 639         {
 640         case -1:
 641                 warn("Unable to fork(): %s\n", strerror(errno));
 642                 return false;
 643
 644         case 0:
 645                 break;
 646
 647         default:
 648                 return true;
 649         }
 650
 651         close(0);
 652         close(1);
 653         close(2);
 654         chdir("/");
 655
 656         clearenv();
 657         setenv("ACTION",    add ? "add" : "remove", 1);
 658         setenv("ZONE",      z->name,                1);
 659         setenv("INTERFACE", d->network->name,       1);
 660         setenv("DEVICE",    d->name,                1);
 661
 662         execl(FW3_HOTPLUG, FW3_HOTPLUG, "firewall", NULL);
 663
 664         /* unreached */
 665         return false;
 666 }